The 1992 debut of Honda’s world-changing CBR900RR Fireblade completely rewrote the design book of supersport motorcycles, introducing a remarkably compact and lightweight configuration.
With relatively tiny proportions and an unprecedented power-to-weight ratio, the Fireblade embodied the origin of the modern supersport motorcycle. This ethos of ‘total control’ would ensure the Fireblade would be the benchmark superbike that all others would be compared against.
The current CBR1000RR Fireblade, launched in 2017 stayed true to the model’s perfect balance of handling, power and control but for the first time ever combined its razor-sharp handling, light weight and smooth power with a sophisticated electronics package. Thus the ‘Total Control’ ethos of the original evolved into ‘Next Stage Total Control’ for the new Fireblade which was offered in three models; the standard, SP, and SP2 – the last of which is a homologation model produced specifically for superbike racing.
Visually the carbon pattern insets and gold striping interwoven into the Tricolour paint mark the Fireblade SP2’s difference over the ‘stock’ machine and gold Marchesini wheels (reducing front/rear wheel inertia by 18/9%) are another change. But the real differences – and what gives the Fireblade SP2 ultimate racing potential – lie inside the engine.
While the 76mm bore is identical to the standard and SP model, the Fireblade SP2 cylinder head runs 1mm larger, 31.5mm diameter intake valves and 1.5mm larger, 25.5mm diameter exhaust valves, with 10°/12° included valve intake/exhaust included valve angles (from 11°/11°). The valve pitches are identical, maintaining cylinder head width.
It runs the same 13.0:1 compression ratio but uses valve shapes and combustion chambers optimised for efficiency. Elongated spark plugs and a water jacket tightly wrapped around the combustion chambers improve cooling; this technology is derived directly from Honda’s RC213V MotoGP machine.
The pistons use an exclusive crown design with heat treatment that strengthens the area around the piston boss, which itself employs a 2.5mm shorter (and 8g lighter per cylinder) piston pin. Ready to house high-lift camshafts the outer diameter of the valve lifter has grown 2mm to 28mm, while total height and thickness have been reduced saving weight.